Remnant retractor collet

ABSTRACT

An improved retractor collet fastens to a pusher rod in a bar machine and retracts the remnant end of a consumed bar. The collet includes a fixed sleeve with an axial bore and an open end for receiving the bar, and a rotatable gripper is housed within the sleeve ahead of a thrust bearing. The gripper is sized to receive and grip the bar and is freely rotatable within the sleeve as the bar is machined. The gripper holds the remnant end of the bar when the collet is retracted to remove the remnant from the machine.

Hesslein et all it REMNANTVRETRAICTOR COLLET 51 May 15, 1973 2,778,650 71/1957 Benjamin et al ..279/46 e r. 2,5 1, 99 50 h ff ..27 4

[76] inventors: Robert J; Hesslein, 3 Bishop Drive, 2 0 9/19 S 3 er 9/ 6Fayetteviue'; R ber w b m Primary Examiner-Gil Weidenfeld 'WOOdWOITh'ROad, Centre Attorney-Cumpton, Shaw & Stephens Square, both of NY. 22Filed: Mar. 23,- 1971 [571 ABSTRACT 21 A L N 127 151 An improvedretractor collet fastens to a pusher rod in 1 pp 0 a bar machine andretracts the remnant end of a consumed bar. The collet includes a fixedsleeve with an [52] US. Cl ..279/46 aXial bore and an p end forreceiving the and 51 Int. Cl. ..B23b 31/00 a rotatable pp is housedWithin the Sleeve ahead 58 Field ,of sea criwi ..279/41, 46, 23, 102;thrust l The gripper is F F" receive and i 287/126 grrp the bar and 1sfreely rotatable within the sleeve as the bar is machined. The gripperholds the remnant end of the bar when the collet is retracted to remove[56] Reierences Cited the remnant from the machine.

1 i UNITED-STATES PATENTS 9 Claims, 3 Drawing Figures 2,343,570 3/1944Nelson ..279/46 X I0 v is m is 2 5 2 24 r 22 v 1\ t M i. l H M I a i '24 i i ,7 -i y x I PAIENIEDHAYISISYS $733,081

INVENTOR. ROBERT J. HESSLEIN ROBERT W CHA BERLIN W yZLI- J AMA AT TORNEYS REMNANT RETRACTOR COLLET Tl-IE INVENTIVE IMPROVEMENT Retractorcollets for bar machines are generally well known. They have resembledconventional collets except that they were rotatably mounted on the endof a pusher rod advancing the bar through the machine. Their function isto grip the trailing end of a bar without interfering with the bar'srotation in the machine, drive the bar along as the pusher rod isadvanced, and gripthe remnant end of the bar to retract it from themachine as the pusher rod is retracted when the bar is consumed.

The invention involves recognition of a way to simplify retractorcollets to reduce their expense and make their use more efficient. Theinvention also aims at a less expensive inventory of different sizes ofretractor collets and easy changeover from one size to another.

SUMMARY OF THE INVENTION DRAWINGS FIG.- 1 is a longitudinal, axial,cross-sectional view of a preferred embodiment ofthe inventive remnantretractor collet;

FIG. 2 is plan view of a gripper tube for use in the inventive collet;and

FIG. 3 is an end elevation of the gripper tube of FIG. 2.

DETAILED DESCRIPTION Remnant retractor collet 10 includes a sleeve 1 Ihaving an axial bore 12 and an open end 13 for receiving a bar 14 forfeeding to a bar working machine such as an automatic screw machine orlathe. A coupler 15 is threaded into the closed end 16 of sleeve 11, andcoupler 15 attaches sleeve 11 to a pusher rod (not shown) for advancingbar 14.

A gripper 20, preferably formed as a split tube, fits loosely in bore 12for free rotation inside sleeve 11. Bore 12 has a region of reducedinside diameter to form an internal collar 17 near open end 13, and theoutside diameter of gripper tube 20 is larger than the inside diameterof collar 17 so that gripper tube 20 cannot escape out open end 13.Gripper tube 20 is preferably formed of hardened and ground spring steelwith a longitudinal slit 21 and a beveled end 22. The inside diameter oftube 20 is sized to receive and grip bar 14 firmly enough for retractingthe remnant end of bar 14. Rather than having a slit 21, gripper tube 20can be deformed in several possible ways to provide a spring grip on bar14. Gripper 20 can also be a socket-shaped element fitting within bore12 and open only at one end for gripping bar 14. Gripper 20 ispreferably free to move axially a small distance within bore 12 as wellas rotate freely within bore 12.

A live bar stop 23 is rotatably housed in bore 12 behind gripper tube20, and the bar-confronting end of stop 23 preferably has a conicalsurface 24 for engaging the trailing end of bar 14. Bar 14 can then passall the way through gripper tube 20 and engage the conic surface 24 oflive stop 23.

A ball bearing 25 is arranged behind live stop 23 and ahead of ball seat26 so as to afford nearly point contact between seat 26 and stop 23.Ball 25 and ball seat 26 are preferably rotatable within bore 12, andalso free to move axially if necessary. Stop 23, ball 25, and seat 26form a thrust bearing arranged behind gripper tube 20 and are designedto accommodate the wear and thrust from turning and pushing forces onbar 14.

A plurality of gripper tubes 20 are preferably available for use insidea sleeve 12 to accommodate different diameters of bars 14. Each size ofgripper tube 20 preferably has a different inside diameter and the sameoutside diameter sized to fit loosely in bore 12. This means that onlygripper tubes 20 need be changed for different sizes of bars 14, andsince gripper tubes 20 are the only parts of collet 10 that need beformed of hardened, spring steel, an inventory of different sizedgripper tubes 20 is much less expensive than a corresponding inventoryof previous retractor collets.

In operation, as collet 10 is pushed against the trailing end of a newbar 14, it drives bar 14 against a work stop or a closed collet of themachine with sufficient force so that bar 14 is pushed into collet 10,into gripper tube 20, and eventually against live stop 23. Gripper 20and live stop 23 rotate with bar 14 inside of sleeve 11 as bar 14 ismachined. The remnant end of bar 14 is held by gripper 20 for retractionfrom the machine when bar 14 is consumed, and a known mechanismwithdraws the remnant from gripper 20 near the end of the retractionstroke. Then a new bar 14 is placed in the machine and the process isrepeated.

Collet l0 improves over prior art retractor collets in forming thegripper element as a relatively small, simple, and interchangeable partwith a fixed, permanent sleeve that also houses a simple and durablethrust bearing. Collet 10 is reliable and effective in operation,simpler and more economical to make, and less expensive in accommodatingdifferent sized bars.

Persons wishing to practice the invention should remember that otherembodiments and variations can be adapted to particular circumstances.Even though one point of view is necessarily chosen in describing anddefining the invention, this should not inhibit broader or relatedembodiments going beyond the semantic orientation of this applicationbut falling within the spirit of the invention. For example, thoseskilled in the art will understand the use and adaptation of theinventive collet to a variety of machines and bar feeding and retractingoperations.

I claim:

1. A remnant retractor collet comprising:

a. a sleeve having an axial bore with a forward end opening forreceiving the trailing end of a bar;

b. means for coupling the rear end of said sleeve to a pusher rod foradvancing said bar so said bar is rotatable relative to said sleeve;

c. a resilient gripper having an outside diameter sized for freerotation within said bore of said sleeve;

d. an internal collar in the region of said forward end of said sleevefor preventing forward movement of 3 said gripper through said endopening of said sleeve;

e. said gripper having an inside diameter sized to receive and grip saidtrailing end of said bar; and

f. rotatable thrust bearing means arranged in said bore of said sleevebehind said gripper and ahead of said coupling means to accommodate theaxial force exerted by said sleeve against the relatively rotatingtrailing end of said bar.

2. The collet of claim 1 wherein said gripper is a split tube open ateach end.

3. The collet of claim 1 including a plurality of said grippers havingdifferent inside diametels and approximately equal outside diameters tofit different sized bars.

4. The collet of claim 3 wherein said grippers are split tubes open ateach end.

5. The collet of claim 1 wherein said thrust bearing means includes arotatable ball bearing.

6. The collet of claim 5 wherein said gripper is a split tube open ateach end.

7. The collet of claim' 6 including a rotatable bar stop elementarranged between said gripper and said ball bearing.

8. The collet of claim 7 including a movable ball seat arranged on theopposite side of said ball bearing from said bar stop.

9. The collet of claim 8 including a plurality of said grippers havingdifferent, inside diameters and approximately equal outside diameters tofit different sized bars.

1. A remnant retractor collet comprising: a. a sleeve having an axialbore with a forward end opening for receiving the trailing end of a bar;b. means for coupling the rear end of said sleeve to a pusher rod foradvancing said bar so said bar is rotatable relative to said sleeve; c.a resilient gripper having an outside diameter sized for free rotationwithin said bore of said sleeve; d. an internal collar in the region ofsaid forward end of said sleeve for preventing forward movement of saidgripper through said end opening of said sleeve; e. said gripper havingan inside diameter sized to receive and grip said trailing end of saidbar; and f. rotatable thrust bearing means arranged in said bore of saidsleeve behind said gripper and ahead of said coupling means toaccommodate the axial force exerted by said sleeve against therelatively rotating trailing end of said bar.
 2. The collet of claim 1wherein said gripper is a split tube open at each end.
 3. The collet ofclaim 1 including a plurality of said grippers haVing different insidediameters and approximately equal outside diameters to fit differentsized bars.
 4. The collet of claim 3 wherein said grippers are splittubes open at each end.
 5. The collet of claim 1 wherein said thrustbearing means includes a rotatable ball bearing.
 6. The collet of claim5 wherein said gripper is a split tube open at each end.
 7. The colletof claim 6 including a rotatable bar stop element arranged between saidgripper and said ball bearing.
 8. The collet of claim 7 including amovable ball seat arranged on the opposite side of said ball bearingfrom said bar stop.
 9. The collet of claim 8 including a plurality ofsaid grippers having different, inside diameters and approximately equaloutside diameters to fit different sized bars.